Apparatus and Method for Imprinting Lines on Direct-Expanded Food Products Having Complex Shapes With Improved Dimensional Quality

ABSTRACT

The improved apparatus includes an improved extruder die assembly comprising a forming section, an injection section, and a converging nozzle section having axially aligned ridgelines which gradually project into the bore of the nozzle as the nozzle converges to gradually disrupt the axial flow of an extrudate at specific peripheral points thereby altering the extrudate&#39;s velocity profile. By gradually disrupting the axial flow in close proximity to the projecting ridgelines prior to its extrusion, the dimensional quality of the resulting direct expanded food piece is greatly improved. Moreover, by carefully positioning the capillary channels of the injection section into that portion of the flowing extrudate not affected by the axially aligned ridgelines, a distinct colored and/or flavored pattern is imparted into the extrudable food mass during the extrusion process while improving the quality of dimensional design aspects of the resulting extruded, complexly shaped, direct expanded food products.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims filing priority rightswith respect to currently pending U.S. patent application Ser. No.10/891,381, filed on Jul. 14, 2004, which is a continuation-in-part ofand claims filing priority rights with respect to U.S. patentapplication Ser. No. 10/109,398, filed on Mar. 28, 2002 (now U.S. Pat.No. 6,783,787); Ser. No. 10/623,048 filed on Jul. 18, 2003 (now U.S.Pat. No. 6,854,970); and Ser. No. 10/622,400 filed on Jul. 18, 2003 (nowU.S. Pat. No. 7,252,847). U.S. patent application Ser. No. 10/623,048and Ser. No. 10/622,400, in turn, are each continuation-in-partapplications of and claim filing priority rights with respect to U.S.patent application Ser. No. 10/047,503 filed on Oct. 29, 2001 (now U.S.Pat. No. 6,620,448). The technical disclosure of all the above-mentionedapplications is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention generally relates to the production of directexpanded (i.e., puff extruded) farinaceous food products utilizing anovel extruder die apparatus. More specifically, the present inventionis concerned with an improved extruder die assembly and method for usingsame to add a fluid additive into an extrudable food mass whileimproving the dimensional quality of the resulting direct expanded foodproducts. In particular, the improved extruder die assembly of thepresent invention may impart a distinct colored and/or flavored patterninto the extrudable food mass during extrusion while also improving thedimensional quality of the resulting complexly shaped direct expandedfood products. The present invention also includes a method andcomposition for producing a dried, flavored, direct-expanded foodproduct requiring no post-extrusion drying or seasoning process byutilizing the improved extruder die assembly.

2. Description of the Related Art

The use of extrusion devices is prevalent in a number of industries,especially the food industry. The use of extrusion devices in thepreparation of direct expanded food products is long practiced. Utilizedto produce a variety of products such as ready-to-eat (R-T-E) cereals,snack foods and confections, extrusion remains prominent among foodprocesses because of its versatility and efficiency.

Food processes utilizing extrusion devices typically include an ediblesubstance such as dough which is introduced into a device and conveyedvia a screw pump to an inlet where the substance is forced through anextruder die assembly. The extruder die assembly may perform a varietyof functions: it may form or shape the extrudate; it may divide theextrudate into a multiple extrudates; it may inject an additivesubstance into the extrudate; and it may compress and reduce thecross-sectional area of the extrudate. Examples of devices used forextrusion of food products are illustrated in U.S. Pat. Nos. 2,858,217;3,314,381; and 5,639,485. While extrusion dies have evolved over theyears, the method by which an additive substance is supplied andinjected into the extrudate has remained essentially unchanged.

For Example, in U.S. Pat. No. 2,858,217 to Benson, the introduction ofcoloring matter, such as a colored liquid dye, is accomplished via aseries of apertures 40, 42, 44 disposed in the bridging strips 32, 34,36 and supplied by horizontal passages 52, 54, 55 which are in fluidcommunication with the dye reservoir 46. The supplying of the liquid dyefrom the dye reservoir 46 to series of apertures 40, 42, 46 is by meansof gravitational force. According to the Benson '217 device, doughmaterial 18 is extruded through a divider block 22 which forces thedough material 18 to divide or spread around the bridging strips 32, 34,36 so that voids 38 are formed into which the coloring matter isintroduced via the series of apertures 40, 42, 44.

Similarly, in U.S. Pat. No. 3,314,381 to Fries et al., the fluidinjection assembly is comprised of a hollow tubular injection member 29in a helical spiral configuration, which includes a bore 37 throughwhich pressurized injection fluid is supplied from a source 25 to aplurality of longitudinally spaced bores 39 into a distributing channel38. The fluid along the length of channel 38 is injected into thepassing dough as a substantially longitudinally continuous spiral bandextending from substantially the central axis of the dough to either theouter face of the dough or a point short thereof. However, the Fries etal. '381 device is primarily adapted to relatively low pressurecomestible extrusions.

Finally, U.S. Pat. No. 5,639,485 to Weinstein et al. and its relatedpatents, disclose a method and apparatus for adding additives in flowingdough to make complexly patterned multicolored extrudates. The Weinsteinet al. '485 invention and its progeny all disclose a high pressureextrusion device comprising an extruder die insert 20 which includesmeans for imparting at least one interstitial gap in the flowing doughby means of a plurality of dividing passageways (e.g., 44, 45, 46)formed by die dividing members 47. An additive (e.g., a food color or asecond colored dough) may be injected via a plurality or array of evenlyspaced food color injection ports 48 formed on the downstream side ofdie dividing member 47. The injection ports 48 are in fluidcommunication with a pressurized color supply 18 by means of a supplyports 52, 54, 56 and supply passageway 50. The color fluid tends to fillthe interstitial gaps in the flowing dough between passageways (e.g.,44, 45, 46) formed by and behind the die dividing members 47 to create aline in the shape of dividing members 47 in the extruded dough. The dieinsert 20 also includes notches 57 which are used to isolate the colorfluid injected into the interstitial gap from spreading to the interiorsurface wall of die insert 20 thereby reducing if not eliminating theleakage on color fluid onto the outside of the extruded dough.Additionally, the die insert 20 can further include a means for sealing(e.g., “O” rings 60 and 62 as depicted) the color fluid supply reservoir58 against premature admixture with dough.

In addition to the die insert element, the Weinstein et al. '485invention also comprises a reducing passageway 25 whereby theextrudate's cross-sectional area is significantly reduced. At highoperating pressures, the convergence of the passageway 25 inherentlycreates a significant back pressure on the downstream side of theextruder die insert 20 which, in turn, can contribute to and promote theclogging of the individual injection ports 48. Moreover, the utilizationof notches 57, sealing means 60, 62 and multiple enclosed injectionports 48 further complicates the design of the die insert making itharder to clean and maintain. Finally, injecting color fluid at discretelocations into downstream voids or interstitial gaps to disperse thefluid in a generally uniform manner requires precise control of flowrates, internal pressures, and viscosity of the extrudate and variousadditives. Furthermore, the design of each die insert 20 is limited tothe physical constraints imposed by the previously mentioned designelements.

What is needed is an extruder die assembly capable of operating at avariety of operating pressures which has improved seal characteristicsand is simpler and easier to maintain and whose injection mechanism isless prone to clogging and blockages.

In addition, extrusion devices are increasingly utilized to impart heatto the base substance during its transit through the extruder device.Typically, a casing surrounding the extrusion chamber is adapted toimpart heat to the substance in accordance with practices commonly knownin the art. For example, cooker extruders are used to prepare cookeddough extrudates that may then be formed into individual cereal or snackpieces, and subsequently baked or fried.

One variation of cooker extruders that is increasingly popular comprisesan extruder wherein the conditions of the extruder and the cooked cerealdough are such that the dough puffs immediately upon being extruded andis cut into individual puffed pieces at the die head. Such a process isreferred to generally as “direct expansion” or “puff extrusion.”

The flavoring of such extruded food products typically comprises eitherflavoring the base substance prior to its introduction to the extruderdevice (i.e., adding a flavoring to the base substance within theextruder device wherein it is admixed utilizing a screw pump mechanism)or flavoring the resulting extruded food piece subsequent to theextrusion process. However, inducing heat to the base substance duringan extrusion process adversely affects the flavoring of the resultingextruded food product. Many flavoring are particularly sensitive to heatinduced during the manufacturing process. For example, spicy flavorings(e.g., green pepper, chipotle, and jalapeño) and salty dairy flavors(e.g., cheddar cheese and sour cream) are particularly susceptible toflavor diminishment or deterioration when exposed to heat for anextended period of time during a direct expansion extrusion process.Even sweet flavorings (e.g., strawberry, chocolate, vanilla, etc.),while more heat tolerant than other flavoring, are, nevertheless,somewhat degraded when exposed to heat during the manufacturing process.Thus, the flavoring of direct expansion food products usually occursduring a separate seasoning step, which occurs subsequent to the directexpansion extrusion process. Flavorings are typically sprinkled on andadmixed with a mass of direct expansion food product on a conveyor beltmechanism or in a tumbling drum mechanism. The tumbling mechanismensures even coverage of the extruded product.

While the adverse effects caused by heat on flavorings can be avoided byutilizing an extruder mechanism which does not induce heat to the basesubstance during an extrusion process, the resulting flavored extrudedpieces will typically still require a subsequent drying process.Moreover, the dried, flavored, extruded pieces will also have to besubsequently baked or fried, which will similarly affect adversely thequality of the flavoring.

Thus, a need also exists for a more efficient system for flavoringextruded food products during a production run of a cooker extrusiondevice. In this regard, it would be particularly desirable if theseasoning or flavoring of direct expanded food products could beaccomplished in a one-step extrusion process (i.e., without a separateseasoning step subsequent to the extrusion process and without asubstantial degradation of heat sensitive flavorings injected prior tothe extrusion process).

Another problematic aspect of direct expansion or puff extrusion devicesinvolves the dimensional quality of the resulting direct expanded foodproducts. Upon exiting the extruder die assembly of a puff extrusiondevice, the extruded mass is directly expanded (e.g., via flash puffing)and typically cut into individual pieces using a reciprocating blademechanism. The resulting individual pieces typically have a uniform,puffed shape with a cross-sectional shape generally corresponding to theoutline of the forming die's exit port. While the characteristics of theresulting individual pieces are satisfactory for simple geometric shapes(e.g., spheres, ovoids, and crescents), the design details of morecomplex shapes tend to be obscured or eliminated.

For example, FIG. 1 a shows the exit face 12 of a forming die 10 used inprior art extruder die assembly. Included within the periphery of theexit face 12 is a complexly shaped exit port 14. The outline 16 of exitport 14 is designed to resemble a hand with four distinct appendages orfingers. When the forming die 10 is utilized in conjunction with aconventional direct expanded food process, the resulting product is auniformly puffed food piece 18 as shown in FIG. 1 b. While the shape ofthe outline 16 of exit port 14 is somewhat discernable in food piece 18,the design details of the four distinct appendages is generallydiminished and obscured. The individual dimensional aspects of the fourdistinct appendages are simply absorbed by the dimensional aspects ofthe palm area of the outline 16 of exit port 14.

A need, therefore, exists for an improved apparatus and method forimparting a distinct colored and/or flavored pattern into an extrudablefood mass during the extrusion process while enhancing the quality ofdimensional design aspects of extruded, complexly shaped, directexpanded food products.

SUMMARY OF THE INVENTION

The present invention overcomes many of the shortcomings inherent inprior art apparatus and methods addressing extruder die assemblies. Thepresent invention comprises an improved extruder die assembly and methodfor using same to impart a distinct colored and/or flavored pattern intoan extrudable food mass during the extrusion process while improving thequality of dimensional design aspects of the resulting extruded,complexly shaped, direct expanded food products.

In one embodiment, the system comprises an extruder die assembly andmethod for using same which includes a forming section and an injectionsection fabricated as a matching set. When properly aligned and coupled,the matching set forms a peripheral reservoir manifold, internal to thedie assembly, through which a fluid additive may be supplied via asupply port to at least one and more preferably a plurality of capillarychannels which in turn impart a distinct cross-sectional design into aflowing mass of a first extrudate.

In another embodiment, the system and method for using the presentinvention includes partitioning the internal peripheral reservoirmanifold so that a plurality of supply ports may be used to allowdifferent colors and/or flavors to be injected at different locations inthe distinct cross-sectional design.

In another embodiment, the system and method for using same utilizesmultiple matched sets of forming sections and injection sections intandem to impart multiple pattern designs into an extrudable food mass.

In another embodiment, the system and method for using same utilizesmultiple matched sets of forming sections and injection sections intandem to impart multiple pattern designs of differing colors and/orflavors into an extrudable food mass.

In another embodiment, the system and method for using same utilizes aconverging nozzle to decrease the extrudate's cross-sectional area whilemaintaining the distinct cross-sectional design pattern imparted intothe extrudate.

Thus, in accordance with one feature of the invention, the presentinvention is comprised of an extruder die assembly capable of operatingat a variety of operating pressures which has improved sealcharacteristics and is simpler and easier to maintain. Moreover, theperformance of the extruder die assembly of the present invention ismore stable in that surging of the fluid additive is inhibited therebyresulting in a continuous well defined pattern being injected into theextrudable food mass.

In accordance with another feature of the invention, the presentinvention is comprised of an extruder die assembly whose injectionmechanism is less prone to clogging and blockages. The system of thepresent invention allows the flow of the extrudable food mass to bemomentarily halted without permanently plugging the supply passagewaysor injection section(s).

A novel feature of the invention is an injection nozzle which suppliesfluid additives from an exterior pressurized source to a supply portformed in the extruder die assembly. The subject injection nozzleexhibits superior sealing qualities in conjunction with simplicity andflexibility. The minimal affected space required to receive the subjectinjection nozzle allows a single extruder die assembly to have more thanone supply port fashioned therein. Thus, multiple injection nozzles maybe used to supply a single extruder die assembly with multiple colorsand/or flavors. The injection nozzle of the present invention alsoexhibits a unique dual seal characteristic, which is particularlyeffective in conditions involving high temperature. The subjectinjection nozzle is also highly flexible in that one injection nozzlemay be used interchangeably with another (i.e., each injection nozzle isnot unique to a particular supply port).

A novel food product may also be produced in accordance with anotherfeature of the invention, wherein a known composition of a farinaceousfood product is extruded through the extruder die assembly of thepresent invention to produce a flavored direct-expanded food productexhibiting enhanced flavor characteristics while requiring nopost-extrusion drying or seasoning process. The injection section of theextruder die assembly is used to impart flavoring additives into theextrudate mass shortly before expansion, thereby preserving theflavoring characteristics of the additive by minimizing the heatexposure of the flavoring additive. The extruder die assembly may alsoinclude static mixing elements downstream from the injection section tohomogenize the flavoring or seasoning media into the flowing mass ofextrudate. In particular, the present invention may be used to combineheat sensitive flavorings into a farinaceous food mixture to produce aflavored, direct expanded, farinaceous food product without the use of adrying apparatus or a seasoning step subsequent to the extrusionprocess.

In yet another embodiment, the improved extruder die assembly of thepresent invention may also include a transition insert section, aplurality of spacer insert elements, an imprinting insert element, and aforming insert element, all of which are coaxially aligned andinterlocking. The improved extruder die assembly of the presentinvention is designed for adaptation to a wide variety ofcommercial-grade extrusion devices common in the food industry. Theimprinting insert element includes at least one prong which, whenproperly configured, is aligned with a corresponding projection in theforming insert element, and momentarily disrupts the axial flow of anextrudate altering its velocity profile. By disrupting the axial flowthe extrudate in close proximity to the projections in the forminginsert element prior to its extrusion, the dimensional quality of theresulting direct expanded food piece is greatly improved.

The axial distance between the one or more prongs and its correspondingprojection may be adjusted as necessary using spacer insert elements tooptimize the dimensional qualities of the resulting food piece dependingupon the particular flow characteristics of each extrudate.

In another embodiment of the present invention, the extruder dieassembly includes a converging nozzle section having axially alignedridgelines which gradually project into the bore of the nozzle as thenozzle converges to gradually disrupt the axial flow of an extrudate atspecific peripheral points thereby altering the extrudate's velocityprofile. By gradually disrupting the axial flow the extrudate in closeproximity to the projecting ridgelines in the converging nozzle prior toits extrusion, the dimensional quality of the resulting direct expandedfood piece is greatly improved. Moreover, by carefully positioning thecapillary channels of the injection section into that portion of theflowing extrudate not affected by the axially aligned ridgelines, adistinct colored and/or flavored pattern may be imparted into theextrudable food mass during the extrusion process while improving thequality of dimensional design aspects of the resulting extruded,complexly shaped, direct expanded food products.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and apparatus of the presentinvention may be had by reference to the following detailed descriptionwhen taken in conjunction with the accompanying drawings, wherein:

FIG. 1 a is an exit face view of a forming die used in prior artextruder die assembly;

FIG. 1 b depicts the resulting direct expanded food piece formed byutilizing the forming die shown in FIG. 1 a in a conventional directexpanded food process;

FIG. 2 a is a cut-away perspective view one embodiment of the extruderdie assembly of the present invention;

FIG. 2 b is a cut-away exploded perspective view of the extruder dieassembly of the present invention shown in FIG. 2 a;

FIG. 3 a is an overhead view of the forming section of the extruder dieassembly of the present invention shown in FIG. 2 a;

FIG. 3 b is a cut-away perspective view of the forming section of theextruder die assembly of the present invention shown in FIG. 3 a;

FIG. 4 a is an overhead view of the injection section of the extruderdie assembly of the present invention shown in FIG. 2 a;

FIG. 4 b is a cut-away perspective view of the injection section of theextruder die assembly of the present invention shown in FIG. 4 a;

FIG. 5 is a perspective in partially exploded view of the exit face of adie plate assembly attached to a food cooker extruder showing anembodiment of the extruder die assembly of the present invention andassociated injection nozzle assemblies;

FIG. 6 a is a partial sectional view of the die plate assembly takenalong lines 6-6 in FIG. 5, showing an embodiment of the extruder dieassembly and injection nozzle of the present invention properly alignedand inserted therein;

FIGS. 6 b and 6 c are enlarged sectional views of the interface betweenthe extruder die assembly and associated injection nozzle shown in FIG.6 a;

FIG. 7 is perspective in partially exploded view of an alternateembodiment of the extruder die assembly of the present inventionillustrating an integral static mixer element;

FIG. 8 a is cross-sectional view of an embodiment of the extruder dieassembly of the present invention;

FIG. 8 b is cross-sectional view of an alternate arrangement of anembodiment of the extruder die assembly of the present invention;

FIG. 9 is an exit face view of a spacer insert element used in anembodiment of the extruder die assembly of the present invention;

FIG. 10 is an exit face view of the imprinting insert element used in anembodiment of the extruder die assembly of the present invention;

FIG. 11 is an exit face view of the forming insert element used in anembodiment of the extruder die assembly of the present invention;

FIG. 12 is an exit face view of an embodiment of the extruder dieassembly of the present invention;

FIG. 13 depicts the resulting direct expanded food piece formed byutilizing an embodiment of the extruder die assembly of the presentinvention;

FIG. 14 a is a cut-away perspective view of yet another alternateembodiment of the extruder die assembly of the present invention, whichincludes a converging nozzle section featuring a complexly shaped axialbore having axially aligned ridgelines;

FIG. 14 b is a cut-away exploded perspective view of the embodiment ofthe extruder die assembly of the present invention shown in FIG. 14 a;

FIG. 15 a is an overhead view of the inlet face of the forming sectionof the extruder die assembly of the present invention shown in FIG. 14a;

FIG. 15 b is a cut-away perspective view of the forming section of theextruder die assembly of the present invention shown in FIG. 15 a;

FIG. 16 a is a cut-away perspective view of the injection section of theextruder die assembly of the present invention shown in FIG. 14 a;

FIG. 16 b is an overhead view of the outlet face of the injectionsection of the extruder die assembly of the present invention shown inFIG. 14 a;

FIG. 17 a is an overhead view of the inlet face of the converging nozzlesection of the embodiment of the extruder die assembly of the presentinvention shown in FIG. 14 a;

FIG. 17 b is an overhead view of the outlet face of the convergingnozzle section of the embodiment of the extruder die assembly of thepresent invention shown in FIG. 14 a; and

FIG. 18 depicts a perspective view of the resulting direct expanded foodpiece formed utilizing the embodiment of the extruder die assembly ofthe present invention shown in FIG. 14 a.

Where used in the various figures of the drawing, the same numeralsdesignate the same or similar parts. Furthermore, when the terms “top,”“bottom,” “first,” “second,” “upper,” “lower,” “height,” “width,”“length,” “end,” “side,” “horizontal,” “vertical,” and similar terms areused herein, it should be understood that these terms have referenceonly to the structure shown in the drawing and are utilized only tofacilitate describing the invention.

DETAILED DESCRIPTION OF THE INVENTION

An extruder die assembly, generally indicated by reference character 100in FIGS. 2 a and 2 b, includes a forming section 200, an injectionsection 300, and a nozzle section 400. The three sections comprising thedie assembly 100 are coaxially aligned and interlocking. Additionally,means for coupling the forming section 200 to the injection section 300are also included.

The extruder die assembly 100 is designed for adaptation to a widevariety of commercial-grade extrusion devices common in the foodindustry. The extruder die assembly 100 is inserted into an appropriatecompartment within an extrusion device (not shown) such that a firstextrudate (e.g., a paste or a cereal dough) is directed down a coaxiallyaligned passageway 210 within the forming section 200 and combined witha fluid additive (e.g., a food coloring dye or a flowable colored and/orflavored food material) in the injection section 300 via supply port 340and annular reservoir R, whereupon the resulting food mass is compressedthrough a converging nozzle bore 420 in the nozzle section 400 toproduce an extruded food product containing a distinct colored and/orflavored pattern.

While the embodiment illustrated is shown as being generally cylindricalin shape, the exterior housing of the die assembly 100 may be of anyshape necessary for adaptation to commercial-grade extrusion devicescommon in the food industry. Similarly, while passageway 210 and bore420 are depicted as having a circular cross sectional area, in otherembodiments, passageway 210 and bore 420 can be fabricated with a morecomplex peripheral configuration to define or define in part theexterior shape or configuration of the finished piece, including bothregular shapes (e.g., stars, rings, geometric shapes) as well asirregular shapes (e.g., animals, vegetables, objects such as trees,cars, etc.).

Referring to the figures, and in particular FIGS. 3 a and 3 b, theforming section 200 is a generally tubular flange element having acentral bore defining a passageway 210. The inlet 212 of the passageway210 is adapted to receive a conduit (not shown) supplying a pressurizedfirst extrudate from an extrusion device (not shown). A plurality ofcounter-sunk coupling holes 202, equally spaced around the periphery ofthe entrance face 204 of forming section 200, are provided for receivingscrews (not shown) for removably coupling the forming section 200 tothreaded holes 302 in the injection section 300. An alignment hole 206extends through the forming section 200 in parallel alignment with thepassageway 210 to receive an alignment knob 306 on the entrance face 304of the injection section 300. When properly seated into the alignmenthole 206, the alignment knob 306 ensures that the axial angularalignment of the injection section 300 in relation to the formingsection 200 is correct.

The outlet portion of the passageway 210 includes a forming die element220 which divides the flow of the first extrudate into at least two, andmore preferably a plurality of adjacent flowing extrudate passagewayssuch as passageways a-g respectively formed by forming die element 220.

The forming section and injection section are fabricated as a matchingset. In general, the outlet portion of the forming section is designedto mate and seal with the inlet portion of the injection section. In oneembodiment, an inner peripheral rim formed in the outlet portion of theforming section is specifically designed to slidably couple and alignwith a central bore in the inlet portion of the injection section. Theinner peripheral rim is defined by a peripheral notch formed in theoutlet face of the forming section. The peripheral notch ischaracterized by a peripheral rim wall which is parallel with andgenerally equidistant from the outer periphery of the centralpassageway. The inner peripheral rim includes a peripheral groove with asemicircular cross-section. A matching peripheral groove with asemicircular cross-section is formed in the base of the central bore ofthe inlet portion of the injection section such that when the formingsection and injection section are slidably coupled and aligned, aninternal peripheral reservoir manifold with a circular cross-section isformed.

Thus, as shown in the figures, and in particular FIGS. 3 b, 4 a, and 4b, when the present invention is realized in an embodiment having agenerally circular cross section, the inner peripheral rim formed in theoutlet portion of the forming section 200 is an annular rim defined byan annular notch, characterized by the annular rim wall 242 and theannular outer ring seal face 240, around the outer periphery of theoutlet face of the forming section 200. The annular rim in the outletportion of the forming section 200 slidably fits into a central bore inthe inlet portion of the injection section 300 defined by the annularbore wall 308 such that the forming section's annular outer ring sealface 240 seats and seals with the injection section's annular outer sealface 304, the forming section's intermediate annular seal face 244 seatsand seals with the injection section's annular intermediate ring sealface 310, and the forming section's inner annular seal face 246 and theexit face 248 of the forming die element 220 seat and seal with theentrance face 322 of the injection section's co-injection die insert320. Moreover, the matching annular peripheral grooves 230 and 330 forman annular internal peripheral reservoir manifold R into which a fluidadditive may be supplied by means of outlet 344 of supply port 340. Whenproperly aligned and coupled, the respective annular seals between theforming section 200 and the matching injection section 300 effectivelyseal and isolate the fluid additive supplied to the reservoir manifold Rfrom inadvertent leakage to the upstream side of the forming die element220 and the outer periphery of the extruder die assembly 100.

The injection section 300 includes a co-injection die insert 320 whichhas profile such that when properly aligned with the forming die element220, passageways a′-g′ are respectively adjoined with passageways a-gformed by forming die element 220. When properly aligned and coupled,the seal between the exit face 248 of the forming die element 220 andthe entrance face 322 of the injection section's co-injection die insert320 ensures that the respective adjacently flowing extrudate passagewaysare unobstructed and contiguous and that the fluid additive contained inthe reservoir manifold R does not inadvertently leak to the upstreamside of the forming die element 220.

The co-injection die insert 320 includes at least one and morepreferably a plurality of capillary channels 352 in the space betweenthe plurality of passageways. The capillary channels 352 are fluidlyconnected to the reservoir manifold R via channel ports 350. Thereservoir manifold R is fluidly connected to a pressurized source offluid additive (not shown) via supply port 340.

When properly aligned and coupled, the seal between the exit face 248 ofthe forming die element 220 and the entrance face 322 of the injectionsection's co-injection die insert 320 ensures that the pressurized fluidadditive supplied to the annular internal peripheral reservoir manifoldR continually charges the capillary channels 352 via channel ports 350whereupon each capillary channel 352 emits at its downstream exit face acontinuous discharge of fluid additive in the general cross-sectionalshape of the capillary channel 352 resulting in a continuous band offluid additive being injected into the transient clefts formed in thefirst extrudate as it exits the adjacent flowing extrudate passagewayssuch as passageways a′-g′. Upon exiting from the individual adjacentflowing extrudate passageways (e.g., passageways a′-g′), the individualadjacently flowing columns of first extrudate coalesce to enclose theinjected bands of fluid additive within a single flow mass therebyimparting a distinct colored and/or flavored pattern into the food mass.

In an alternative embodiment of the present invention, the injectionsection 300 may include multiple supply ports 340 fluidly connected toseparate pressurized sources of fluid additive. In such an embodiment,the annular internal peripheral reservoir manifold R may be divided intomultiple segregated quadrants fluidly connecting individual pressurizedsources of fluid additive to specific capillary channels 352 allowing adistinct pattern of multiple colors and/or flavors to be imparted intothe food mass.

In one embodiment of the present invention, the exit face 362 of theinjection section 300 is generally designed to mate and seal with theinlet face 404 of the nozzle section 400. With the exception of theco-injection die insert 320, the inlet face 404 of the nozzle section400 is essentially a mirror image of the exit face 362 of the injectionsection 300. In general, the nozzle section 400 includes an inlet with aperiphery matching the periphery of the forming section's passageway.The nozzle section further includes a passageway coaxially aligned withthe forming section's passageway which converges to an outlet. As thepassageway converges, the passageway's cross-sectional decreases whileits aspect ratio is generally maintained. Thus as shown in the figures,and in particular FIGS. 2 b and 4 b, when the present invention isrealized in an embodiment having a generally circular cross section, thenozzle section 400 includes an inlet 410 with an inner annular peripherywhich matches the periphery of the forming section's passageway 210. Thenozzle section further includes a passageway 420 coaxially aligned withthe forming section's passageway 210 which converges to an outlet 430.

In an actual embodiment having a circular cross section as illustratedin FIG. 1 b, the diameter of converging nozzle bore passageway 420 isreduced from 0.664 inches at inlet 410 to 0.332 inches at outlet 430,wherein the cross-sectional area of the converging nozzle bore 420 isreduced by a factor greater than 4:1 between the inlet and the outlet ofthe extrusion nozzle bore. In another such embodiment, the diameter ofconverging nozzle bore passageway 420 is further reduced from 0.664inches at inlet 410 to 0.153 inches at outlet 430, wherein thecross-sectional area of the converging nozzle bore passageway 420 isreduced by a factor less than 20:1 between the inlet and the outlet ofthe extrusion nozzle bore.

Alternatively, in another embodiment of the present invention, multiplesets of matching forming/injection sections may be adjoined in a tandemor series arrangement. In such an embodiment, the inlet face of a secondset's forming section is designed to mate and seal with the exit face ofa first set's injection section. Arranging multiple sets of matchingforming/injection sections in tandem allows multiple pattern designs ofdiffering colors and/or flavors to be imparted into an extrudable foodmass.

As previously noted, the extruder die assembly 100 of the presentinvention is designed for adaptation to a wide variety ofcommercial-grade extrusion devices common in the food industry. Theextruder die assembly 100 is typically inserted into a sealablecompartment attached to or within an extrusion device (not shown), suchthat the inlet 212 of the forming section 200 of the extruder dieassembly 100 is connected via a conduit to an output port of theextrusion device. For example, as illustrated in FIG. 5, such acompartment may comprise a die plate assembly 500 attached to the outletsection of a conventional cooker extruder device. The die plate assembly500 includes a main die plate 510 having a main bore 512 definedtherethrough for receiving an extruder die assembly 100. Thecircumferential dimensions of the main bore 512 is complementary to thatof the extruder die assembly 100, so as to ensure a snug fit and minimalextrudate leakage therebetween. When an extruder die assembly 100 isinserted into the main bore 512 of the main die plate 510, the outlet430 of the nozzle section 400 protrudes slightly past the exit face 514of the main die plate 510.

The main die plate 510 also includes an injection port 520 formed in thesidewall 516 of the main die plate 510 for receiving an injection nozzle600. The injection port 520 extends through the sidewall 516 to the mainbore 512 at an angle generally perpendicular to the longitudinal axis ofmain bore 512. The injection port 520 is further positioned such thatwhen an extruder die assembly 100 is inserted into and properly alignedwith the main die plate 510, the injection port 520 aligns with acorresponding supply port inlet 342 formed in the injection section 300of the extruder die assembly 100. The main die plate 510 may furtherinclude additional injection ports (e.g., 522) for receiving additionalinjection nozzles (e.g., 602), for use with an extruder die assembly 100having multiple supply port inlets 342 formed in the injection section300 thereof. When not required, the additional injection ports (e.g.,522) may be sealed with a suitable plug device (not shown).

In addition, the die plate assembly 500 also typically includes aconventional feed plate (not shown) which seals the entrance face of themain die plate 510 and has a passageway defined therethrough which actsas a conduit between the output port of the extrusion device and theinlet 212 of the forming section 200 of the extruder die assembly 100.The feed plate may also provide attachment points for connecting the dieplate assembly 500 to the outlet section of the extrusion device.

Referring now to the Figures, and in particular to FIGS. 6 a, 6 b and 6c, which depict various cross-sectional views of the die plate assemblyillustrated in FIG. 5, a novel feature of the invention is shown, whichcomprises an injection nozzle 600 that supplies fluid additives from anexterior pressurized source to a supply port 340 formed in the injectionsection 300 of the extruder die assembly 100. The injection nozzle 600of the present invention exhibits enhanced sealing characteristics whilesupplying pressurized fluid additives to an extruder die assembly 100inserted in a die plate assembly attached to a conventionalcooker-extruder device.

The injection nozzle 600 generally comprises an inlet section 610, amid-section 620, and a outlet section 630. The inlet section 610 isdesigned to receive and couple with a pressurized additive supply line670, 672 so as to establish fluid communication with the exteriorpressurized source. In the embodiment shown in the Figures, the inletsection 610 comprises a standard hexagonal NPT threaded female fittingwhich is designed to engage a conventional threaded male fitting 660,662 attached to the pressurized additive supply line 670.

The mid-section 620 comprises an externally threaded barrel having asmooth-bore interior passageway 616 in fluid communication with an inletspace 612 defined in the inlet section 610. The threaded mid-section 620allows the injection nozzle 600 to be securely mounted into the threadedinjection port 520 formed in the main die plate 510, thus forming aleak-proof assembly.

The outlet section 630 comprises a smooth, tapered end having adischarge port 618 at its distal end which is in fluid communicationwith the interior passageway 616. The diameter of the discharge port 618is typically less than the diameter of the supply port 340. The outletsection 630 is generally paraboloididal shaped having a spherical tip ofa given radius r₁. The spherical tip of the outlet section 630 iscomplementary with the spherical concavity of a given radius r₂ whichdefines the supply port inlet 342 formed in the injection section 300 ofthe extruder die assembly 100. The complementary shapes of the sphericaltip of the outlet section 630 and the supply port inlet 342 provide arelatively larger contact area per unit volume of perforation inside theinjection section 300 of the extruder die assembly 100, therebyresulting in an enhanced sealing mechanism. The resulting increase inthe metal-to-metal contact between the outlet section 630 of theinjection nozzle 600 and the supply port inlet 342 thereby facilitates anon-invasive fluid connection with robust sealing characteristics.

Thus, in addition to the threaded portion 614 of the inlet section 610,which effectively seals the connection between the injection nozzle 600and the pressurized additive supply line 670, the injection nozzle 600of the present invention exhibits a unique dual seal characteristic.First, the threaded mid-section 620 effectively seals the injection port520 preventing extrudate from leaking out from the interior main bore512. Second, the complementary shapes of the spherical tip of the outletsection 630 and the supply port inlet 342 effectively seals thepressurized fluid additives from leaking out to the outer periphery ofthe extruder die assembly 100.

The dual seal characteristic is particularly effective in conditionsinvolving high temperature. In such conditions, components of the dieplate assembly 500 typically expand, oftentimes resulting in acorresponding increase in the gap between the extruder die assembly 100and the interior main bore 512. The dual seal characteristic of theinjection nozzle 600 allows both sealing mechanisms to be adjusted,independent of one another, in response to changes induced by hightemperature conditions.

Furthermore, the injection nozzle 600 of the present invention promotesa simpler and more flexible injection system. For example, while intheory a sealing thread mechanism could be extended along the entirelength of the nozzle, this would require a much larger volume ofperforation inside the injection section of an extruder die assembly toachieve an equivalent contact and sealing area. Moreover, to insure acontinuous threaded seal, the bore of the injection port and the supplyport inlet would have to be threaded concurrently, thereby dictating amatched set arrangement comprised of an injection nozzle, an injectionsection, and a die plate.

On the other hand, the reduced injection section perforation requirementof the injection nozzle 600 of the present invention allows greaterflexibility in the number of nozzles used and the positioning of thenozzles in a particular application. Moreover, the injection nozzle 600of the present invention allows greater simplicity while improving theflexibility of the entire system in that generic components may befashioned so as to be essentially interchangeable with like genericcomponents. For example, the injection nozzle 600 may standardized so asto be interchangeable with any other generic injection nozzle. Thedimensions and position of the supply port inlet 342 formed in assortedinjection sections may also be standardized allowing a generic injectionnozzle having a standardized tip to be used with all of them. Inaddition, the dimensions of the threaded injection ports on the main dieplate may be standardized so as to accommodate all injection nozzleshaving a generic threaded barrel mid-section. Likewise, the position ofthe threaded injection ports on the main die plate may be standardizedso as to align with the supply port inlet 342 on all extruder dieassemblies having a generic injection sections. Thus, by standardizingthe injection nozzle 600, the injection port 520, and supply port inlet342, extruder die assemblies having different forming die elements 220and co-injection die inserts 320 are easily interchangeable with oneanother.

While the embodiment of the injection nozzle 600 illustrated in theFigures is shown as a unitary component, it is understood that othervariants of the injection nozzle 600 of the present invention may becomprised of separate sections which are selectively coupled to oneanother.

In yet another embodiment of the present invention, a known extrudatecomposition of a farinaceous food product is extruded through theextruder die assembly 100 to produce a flavored direct-expanded foodproduct that exhibits enhanced flavor characteristics requiring nopost-extrusion drying or seasoning process. The production of a flavoredextruded food product requiring only minimal post-extrusion processingfor drying and seasoning is very appealing because of the obvioussimplification in the manufacturing process. An essential feature ofthis embodiment of the invention is the ability to add a flavoringadditive in a one-step, direct-expanded extrusion process withoutsubstantially degrading the flavoring characteristics of the additive.

U.S. Pat. No. 4,869,911 to Keller, the technical disclosure of which ishereby incorporated herein by reference, discloses a composition offarinaceous food product that is well suited for use as the flowing massof a first extrudate in the present invention. Such an extrudatecomposition comprises a fluid farinaceous food mixture containing fromabout 5 weight percent to about 17 weight percent of at least oneplasticizer selected from monosaccharides, polysaccharides, and ediblealcohols, including ethanol and glycerol, and having a moisture contentfrom about 9 weight percent to about 17 weight percent.

The food material which may be used in the process of the invention canbe any farinaceous material. The material will generally be in granularor powdered form such as meal, flour, or starch derived from corn,wheat, rice, oats, barley, potatoes, rye, tapioca, and other cerealcrops, legumes or tubers. The preferred farinaceous material is cornmeal. The granular or powdered farinaceous food mixture used in theprocess contains between about 9 weight percent and about 17 weightpercent moisture, based on total weight of the mixture. The farinaceousmaterial, as it is provided from a flour milling operation, usuallycontains sufficient moisture to provide this level. However, ifnecessary, a small amount of water can be added to achieve the desiredlevel.

The plasticizer is selected from the group consisting ofmonosaccharides, polysaccharides, edible alcohols and mixtures thereof.Mixtures of polysaccharides employed preferably have a substantialportion of this mixture consisting of mono-, di-, and tri-saccharides.Useful monosaccharides include, for example, glucose (dextrose) andfructose. The useful polysaccharides include disaccharides, such assucrose and maltose, and mixtures of various chain length saccharides,such as corn syrup solids, maltodextrins, and polydextrose. The usefuledible alcohols include ethanol and glycerol.

It is preferred to use plasticizers selected from the group consistingof sucrose, corn syrup solids, maltodextrin, polydextrose, and glycerol.Corn syrup solids of varying dextrose equivalents (DE) have been usedsuccessfully. One embodiment of the subject invention uses Maltrin® M365(DE 36) manufactured and sold by Grain Processing Corporation ofMuscatine, Iowa which contains about 50% saccharides of chain length of3 saccharide units or less. However, other polysaccharide mixtureshaving other dextrose equivalents may be used. For example, FRO-DEX® Z24 (DE 28) manufactured by American Maize-Products Company of Hammond,Ind. contains about 25% mono-, di-, and tri-saccharides and FRO-DEX® 42(DE 42) contains about 45% mono-, di-, and tri-saccharides. Both ofthese have performed similarly when compared with the Maltrin® M365. Theparticular choice of plasticizer may depend on a number of practicalfactors, including cost and the flavor desired in the end product. Sincethe expanded farinaceous product may be combined with a salty flavoring(e.g., a savory cheese flavoring), it is often desired that thefarinaceous product have a minimal amount of sweetness. Large amounts ofsucrose, dextrose, or fructose should be avoided in such case. Cornsyrup solids or maltodextrins, on the other hand, are only slightlysweet and polydextroses are essentially non-sweet. Glycerol has a slightsweetness, but its flavor is generally not considered agreeable whenused at relatively high concentrations.

For producing a low-sweetness, direct-expanded farinaceous product, amixture containing from about 4.0% to 6.0% corn syrup solids, from about0.5% to 2.0% sucrose, from about 3.0% to 6.0% polydextrose and fromabout 0.5% to 2.5% glycerol, is preferred as the employed plasticizercomponent, based on the total weight of the farinaceous food mixturewhich is fed to the extrusion device.

The following example is intended to further illustrate the knownextrudate composition of the invention and is not intended to limit thescope of the invention in any way.

Example

A non-sweet, whole wheat flavored product was prepared from thefollowing ingredients:

Ingredients Parts By Weight Whole Wheat Flour 58.09 Corn Cones (CornMeal) 28.00 Corn Syrup Solids (Dextrose Equivalent = 34-38) 5.00Polydextrose 3.70 Sucrose 1.20 Glycerol 2.50 Salt 0.50 Monoglycerides0.30 Annatto Powder 0.01 Water 0.70 100.00

Whereas the preceding is directed to the preparation of low sweetnessexpanded farinaceous products, this invention may also be used for thepreparation of moderate to high sweetness expanded farinaceous products.This can be accomplished by using higher levels of the sweeter tastingplasticizers, such as sucrose, fructose, and glucose or other sweetenersknown to those skilled in the art. In this case, the sweeter tastingplasticizers can be used alone or in combination with the less sweetplasticizers at levels of from about 6.0 weight percent to about 15.0weight percent.

If desired, other conventional additives can be present in thefarinaceous food mixture. For example, emulsifiers, salt, fats, fooddyes and flavorings may be present in the mixture in the amountsnecessary to provide a desired effect.

Thus, in accordance with the general parameters of the presentinvention, the known extrudate composition is extruded in a standardtwin- or single-screw extrusion device fitted with the extruder dieassembly 100. A flowing mass of the known extrudate composition isdirected to the inlet 212 of the passageway 210 within the formingsection 200 and combined with a flavored fluid additive (i.e., aflavoring and/or flavored food material) in the injection section 300.The flavored fluid additive may comprise a heat sensitive flavoring(e.g., spicy flavorings such as green pepper, chipotle, and jalapeño; orsalty dairy flavors, such as savory cheese and sour cream) or a heattolerant flavoring (e.g., sweet flavorings such as strawberry,chocolate, vanilla, etc.). While heat tolerant flavorings are lesssusceptible to the adverse effects of heat induced during themanufacturing process, they can, nevertheless, benefit from the methodof the present invention in that overall flavor loss is reducedproducing a higher intensity of flavor at reduced concentrations.

While the extruder die assembly of the present invention is capable ofimparting flavored fluid additive in a distinct flavor pattern in theflowing mass of the known extrudate composition, the extruder dieassembly may be constructed so as to maximize the amount of flavoredfluid additive that may be imparted into the flowing extrudatecomposition with no regard for any corresponding pattern. For example,as shown in FIG. 7, in a preferred embodiment the extruder die assembly100A may comprise co-injection die insert 320A featuring a cross-hatcheddesign. The cross-hatch design maximizes the amount of flavored fluidadditive imparted into the cross-section of the flowing extrudate. Theextruder die assembly 100A may also include static mixing elements(e.g., 700A, 700B, 700C) located downstream from the co-injection dieinsert 320A of the injection section 300A. The static mixing elements(e.g., 700A, 700B, 700C) serve to homogenize the flavoring or seasoningmedia throughout the flowing mass of extrudate. The inlet of the nozzlesection 400A may be adjusted to accommodate the inclusion of staticmixing elements (e.g., 700A, 700B, 700C) within the extruder dieassembly 100A.

After passing through the injection section 300A and any static mixingelements (e.g., 700A, 700B, 700C), the resulting flavored food mass isthen compressed through a converging nozzle bore in the nozzle section400A such that the pressure in nozzle bore is equal to or in excess ofthe vapor pressure of the water in the flavored extrudate mixture, andflavored extrudate mixture through a profile die (e.g., outlet 430A)into a zone of ambient pressure below the vapor pressure of the water inthe mixture. As the flavored extrudate mixture emerges from the die intothe zone of reduced pressure, a portion of the water in the mixture isvaporized, thereby causing the product to expand. The resulting extrudedflavored food product has a moisture content from about 4 weight percentto about 8 weight percent and a water activity (A_(w)) from about 0.30to about 0.45.

The extrusion device of the present invention must be capable ofgenerating super-atmospheric pressures and elevated temperatures in thematerial being extruded. Preferably, the extruder employed is a twinscrew extruder. The twin screw extruder houses two adjacent, parallelscrews which are operated in a co-rotating mode. Suitable twin screwextruders can be obtained commercially and include, for example, aBaker-Perkins model MPF-50D twin screw extruder.

In the practice of this invention, it is preferred to employ a screwconfiguration which imparts relatively low shear forces to thefarinaceous food material. A preferred screw for use in conjunction witha Baker Perkins MPF-50D twin screw extruder has the followingconfiguration, proceeding from the inlet of the extruder barrel towardsthe extruder die assembly 100A:

First, a 10″ long metering screw;

Second, a 3½″ long 30° forward paddle section;

Third, a 3″ long single lead screw;

Fourth, a 2″ long 60° forward paddle section;

Fifth, a 6″ long single lead screw;

Sixth, a 2″ long 60° forward paddle section;

Seventh and last, a 3″ long single lead screw.

The farinaceous food mixture is placed in a feed hopper which feeds theextruder barrel. As the mixture is moved through the extruder barrel bythe action of the rotating extruder screws, the farinaceous food mixturebecomes plasticized and flowable. The heat required to plasticize themixture is generated by the shearing action of the screws. Heating andcooling devices can also be mounted along the extruder to impart orremove heat in order to obtain the desired temperature profile.

As the farinaceous food material moves through the extruder barrel, thebarrel pressure increases. The pressure in the extruder barrel equals orexceeds the vapor pressure of the water in the farinaceous food mixtureat all times, thus preventing the water from vaporizing prior toemergence from the extruder.

The plasticized farinaceous food mixture exits the extruder barrel andis directed to the inlet of the passageway within the forming section200A and combined with a fluid additive (i.e., a flavoring and/orflavored food material) in the injection section 300A and extrudedthrough outlet 430A of nozzle section 400A.

The hot, plasticized, farinaceous food mixture emerges from the outlet430A into a zone of ambient pressure below the vapor pressure of thewater in the mixture; that is, normal atmospheric pressure. Uponemerging from the extruder die assembly 100A, the now flavoredplasticized, farinaceous food mixture is exposed to the reduced pressureenvironment, thus readily allowing a portion of the water in the mixtureto vaporize so that there is formed a highly porous, puffed, cellularbody. In the process of so doing, the residual moisture in thefarinaceous product is reduced to a level from about 4 weight percent toabout 8 weight percent.

Any suitable die configuration can be employed, depending on theparticular product which one desires to make by the process of theinvention. For example, as shown in the FIG. 7, the outlet 430A ofextruder die assembly 100A may have a circular cross-sectional area oran “O”-shaped opening to produce a rod of extrudate or ball-shapedextrudate.

As previously indicated, the resulting extruded food product does notrequire the use of a drying apparatus such as an oven to removemoisture. As it emerges from the outlet 430A of the extruder dieassembly 100A, the extrudate typically has a temperature from about 121°C. to about 163° C. and is soft, yet self-supporting. The product can besubjected to further processing, e.g., segmenting and bagging, etc., assoon as it has cooled sufficiently to become rigid and dimensionallystable. If desired, air cooling or other means may be employed to assistin cooling the extrudate. By eliminating the drying and seasoning stagefrom the production process, the total length of a production line,excluding the extruder, for an expanded, farinaceous food product istypically reduced from about 130 feet to 30 feet or less.

The expanded product is usually cooled to near ambient temperature inabout two minutes. The texture is crisp and crunchy, even though adrying oven was not used. Thus, the resulting extruded food product issuitable for providing a shelf-stable snack product.

While simple geometric shapes (e.g., a spheres, ovoids, and crescents)may be produced using a simple extruder die outlet similar to that shownin FIG. 7, producing a suitable complexly shaped extruded piece requiresfurther refinement of the extruder die outlet. As mentioned previously,a problematic aspect of direct expansion or puff extrusion devicesinvolves the dimensional quality of the resulting direct expanded foodproducts. The resulting individual pieces typically have a uniform,puffed shape with a cross-sectional shape generally corresponding to theoutline of the extruder die outlet. While satisfactory for simplegeometric shapes, the dimensional design details of more complex shapestend to be obscured or eliminated. Thus, the present invention includesan improved extruder die outlet assembly for improving the dimensionaldesign quality of complexly shaped puff extruded pieces.

Referring now to FIG. 8 a, a cross-sectional view of an embodiment ofthe extruder die outlet assembly 20 of the present invention is shown.As shown in FIG. 8 a, the improved extruder die outlet assembly 20 mayinclude a transition insert section 26, a plurality of spacer insertelements 30, an imprinting insert element 40, and a forming insertelement 50, all of which are coaxially aligned and interlocking.

The extruder die outlet assembly 20 of the present invention is designedfor adaptation to a wide variety of commercial-grade extrusion devicescommon in the food industry. While the embodiment illustrated is shownas being generally cylindrical in shape, the exterior housing of theextruder die outlet assembly 20 may be of any shape necessary foradaptation to commercial-grade extrusion devices common in the foodindustry. The extruder die outlet assembly 20 is inserted into theappropriate compartment within an extrusion device (not shown) andconnected to a coaxially aligned supply conduit 24 having a passageway25 whereby an extrudate 22 (e.g., a paste or a cereal dough) is directedthrough the assembly 20. Upon exiting the improved extruder die outletassembly 20, the extrudate 22 is thereupon directly expanded and cutinto individual pieces in the conventional manner.

The transition insert section 26 attaches to the supply conduit 24 anddirects the flow of extrudate 22 through passageway 28 to a passagewaydefined by apertures in each of the spacer insert elements 30. The crosssectional area of the passageway 28 defined through the transitioninsert section 26 may be reduced as necessary to smoothly transition theflow of extrudate 22 from the passageway 25 of supply conduit 24 to thepassageway defined by apertures in each of the plurality of spacerinsert elements 30. Of course, the transition insert section 26 may bedispensed with entirely if the supply conduit 24 may be attacheddirectly to the plurality of spacer insert elements 30.

FIG. 9 illustrates the exit face 32 of spacer insert element 30. Each ofthe plurality of spacer insert elements 30 includes a matching aperture34 defined therethough having a circumference 36, such that whencoaxially aligned, the plurality of spacer insert elements 30 define apassageway through which the extrudate 22 may flow.

Referring now to FIG. 10, an embodiment of the exit face 42 of theimprinting insert element 40 is illustrated. The imprinting insertelement 40 includes an aperture 44 defined therethough having acircumference 46 which generally corresponds to the circumference 36 ofthe aperture 34 defined in the spacer insert elements 30, with theexception that the aperture 44 of imprinting insert element 40 includesone or more prongs 48 projecting into the aperture 44.

FIG. 11 shows an embodiment of a forming insert element 50 used in thepresent invention. The forming insert element 50 includes an aperture 54defined therethough having a complexly shaped circumference 56. Thecomplex shape of circumference 56 is defined by one or more projections58 which extend into the center of aperture 54.

As shown in the exit face view 52 of an embodiment of the extruder dieoutlet assembly of the present invention illustrated in FIG. 12, whenthe improved extruder die outlet assembly 20 of the present inventionillustrated in FIGS. 8 a and 8 b is properly assembled and configured,each of the projections 58 of the forming insert element 50 is alignedwith a prong 48 of the imprinting insert element 40. The prongs 48momentarily disrupt the axial flow of the extrudate 22 altering itsvelocity profile prior to its extrusion through the aperture 54 of theforming insert element 50. By disrupting the axial flow of the extrudate22 in the vicinity of the projections 58 in the forming insert element50 prior to its extrusion, the dimensional quality of the resultingdirect expanded food piece is greatly improved. As shown in FIG. 13, theresulting food piece 70 exhibits an improved three-dimensional qualitysuch that each of the appendages 72 a-d is more clearly defined anddistinguishable from one another.

The axial distance between the one or more projections 58 and itscorresponding prongs 48 may be adjusted as necessary to optimize thedimensional qualities of the resulting food piece depending upon theparticular flow characteristics (e.g., flow velocity, viscosity, andtexture) of each extrudate 22. For example, as shown in FIG. 8 a, in oneconfiguration of an embodiment of the extruder die outlet assembly 20,the imprinting insert element 40 is positioned directly upstream of theforming insert element 50. Alternatively, as shown in FIG. 8 b, inanother configuration of the embodiment of the extruder die outletassembly 20 a, two spacer insert elements 30 are inserted between theimprinting insert element 40 and the forming insert element 50. Thethickness of each individual imprinting insert element 30 may be variedto allow incremental change of the axial distance between the imprintinginsert element 40 and the forming insert element 50. The axial distancebetween the imprinting insert element 40 and the forming insert element50 varies from 5 mm-55 mm, but in a preferred embodiment is 10 mm.

Those skilled in the art will recognize that the extruder die outletassembly 20 shown in FIG. 8 a may also be incorporated into the extruderdie assemblies shown in FIGS. 2 a and 7 in a variety of configurations.For example, in one arrangement the converging nozzle section 400, 400Amay be configured to incorporate a transition insert section 26 and itsassorted insert elements either separately or as an integrated unit.While such a configured converging nozzle will produce a complexlyshaped direct expanded food product having improved dimensionalqualities, the design of a distinct colored and/or flavored patternimparted into the extruded food mass will often be disturbed by the aprong 48 of the imprinting insert element 40. Thus, it is necessary tofurther refine the design of the converging nozzle so that a distinctcolored and/or flavored pattern imparted into the extruded food mass isnot disturbed by the mechanism which improves the dimensional quality ofthe resulting direct expanded food piece.

Referring now to FIGS. 14 a and 14 b, a preferred embodiment of theextruder die assembly of the present invention is shown. The extruderdie assembly, generally indicated by reference character 1000 includes aforming section 1200, an injection section 1300, and a nozzle section1400. As with the previous embodiments, the three sections comprisingthe die assembly 1000 are coaxially aligned and interlockingAdditionally, means for coupling the forming section 1200 to theinjection section 1300 are also included. While the illustratedpreferred embodiment is shown as being generally cylindrical in shape,the exterior housing of the die assembly 1000 may be of any shapenecessary for adaptation to commercial-grade extrusion devices common inthe food industry.

As with the previous embodiments, the preferred embodiment of theextruder die assembly 1000 is designed for adaptation to a wide varietyof commercial-grade extrusion devices common in the food industry. Theextruder die assembly 1000 is inserted into an appropriate compartmentwithin an extrusion device (not shown) such that a first extrudate(e.g., a paste or a cereal dough) is directed down a coaxially alignedpassageway 1210 within the forming section 1200 and combined with afluid additive (e.g., a food coloring dye or a flowable colored and/orflavored food material) in the injection section 1300 via supply port1340 and annular reservoir R′, whereupon the resulting food mass iscompressed through a complexly shaped converging nozzle bore 1420 in thenozzle section 1400 to produce a complexly shaped extruded food productcontaining a distinct colored and/or flavored pattern and havingimproved dimensional qualities.

The forming section 1200 and injection section 1300 of the preferredembodiment 1000 are essentially identical in form and function as thepreviously described embodiments. Thus, as shown in FIGS. 15 a and 15 b,the forming section 1200 is a generally tubular flange element having acentral bore defining a passageway 1210. The inlet 1212 of thepassageway 1210 is adapted to receive a conduit (not shown) supplying apressurized first extrudate from an extrusion device (not shown). Aplurality of counter-sunk coupling holes 1202, equally spaced around theperiphery of the entrance face 1204 of forming section 1200, areprovided for receiving screws (not shown) for removably coupling theforming section 1200 to threaded holes 1302 in the injection section1300. An alignment hole 1206 extends through the forming section 1200 inparallel alignment with the passageway 1210 to receive an alignment knob1306 on the entrance face of the injection section 1300. When properlyseated into the alignment hole 1206, the alignment knob 1306 ensuresthat the axial angular alignment of the injection section 1200 inrelation to the forming section 1200 is correct.

The outlet portion of the passageway 1210 includes a forming die element1220 which divides the flow of the first extrudate into at least two,and more preferably a plurality of adjacent flowing extrudatepassageways.

As with the previously described embodiments, the forming section 1200and injection section 1300 of the preferred embodiment of the extruderdie assembly 1000 are fabricated as a matching set. In general, theoutlet face of the forming section is designed to mate and seal with theinlet face of the injection section. In one embodiment, an innerperipheral rim formed in the outlet face of the forming section isspecifically designed to slidably couple and align with a central borein the inlet face of the injection section. The inner peripheral rim isdefined by a peripheral notch formed in the outlet face of the formingsection. The peripheral notch is characterized by a peripheral rim wallwhich is parallel with and generally equidistant from the outerperiphery of the central passageway. The inner peripheral rim includes aperipheral groove with a semicircular cross-section. A matchingperipheral groove with a semicircular cross-section is formed in thebase of the central bore of the inlet portion of the injection sectionsuch that when the forming section and injection section are slidablycoupled and aligned, an internal peripheral reservoir manifold R′ isformed.

Thus, as shown in the figures, and in particular FIGS. 14 a, 15 a, and15 b, the inner peripheral rim formed in the outlet face of the formingsection 1200 is an annular rim defined by an annular notch,characterized by the annular rim wall 1242 and the annular outer ringseal face 1240, around the outer periphery of the outlet face of theforming section 1200. The annular rim in the outlet face of the formingsection 1200 slidably fits into a central bore in the inlet face of theinjection section 1300 defined by the annular bore wall 1308 such thatthe forming section's annular outer ring seal face 1240 seats and sealswith the injection section's annular outer seal face 1304, the formingsection's intermediate annular seal face 1244 seats and seals with theinjection section's annular intermediate ring seal face 1310, and theforming section's inner annular seal face 1246 and the exit face 1248 ofthe forming die element 1220 seat and seal with the entrance face 1322of the injection section's co-injection die insert 1320. Moreover, thematching annular peripheral grooves 1230, 1330 form an annular internalperipheral reservoir manifold R′ into which a fluid additive may besupplied. When properly aligned and coupled, the respective annularseals between the forming section 1200 and the matching injectionsection 1300 effectively seal and isolate the fluid additive supplied tothe reservoir manifold R′ from inadvertent leakage to the upstream sideof the forming die element 1220 and the outer periphery of the extruderdie assembly 1000.

As with the previously described embodiments, the injection section 1300includes a co-injection die insert 1320 which has profile such that whenproperly aligned and coupled with the forming die element 1220, the sealbetween the exit face 1248 of the forming die element 1220 and theentrance face 1322 of the injection section's co-injection die insert1320 ensures that the respective adjacently flowing extrudatepassageways are unobstructed and contiguous and that the fluid additivecontained in the reservoir manifold R′ does not inadvertently leak tothe upstream side of the forming die element 1220.

The co-injection die insert 1320 includes at least one and morepreferably a plurality of capillary channels 1352 in the space betweenthe plurality of passageways. The capillary channels 1352 are fluidlyconnected to the reservoir manifold R′ via channel ports 1350. Thereservoir manifold R′ is fluidly connected to a pressurized source offluid additive (not shown) via supply port 1340. Thus, as with thepreviously described embodiments, when properly aligned and coupled, theseal between the exit face 1248 of the forming die element 1220 and theentrance face of the injection section's co-injection die insert 1320ensures that the pressurized fluid additive supplied to the annularinternal peripheral reservoir manifold R′ continually charges thecapillary channels 1352 via channel ports whereupon each capillarychannel 1352 emits at its downstream exit face a continuous discharge offluid additive in the general cross-sectional shape of the capillarychannel 1352 resulting in a continuous band of fluid additive beinginjected into the transient clefts formed in the first extrudate as itexits the adjacent flowing extrudate passageways. Upon exiting from theindividual adjacent flowing extrudate passageways, the individualadjacently flowing columns of first extrudate coalesce to enclose theinjected bands of fluid additive within a single flow mass therebyimparting a distinct colored and/or flavored pattern into the food mass.

As with the previously described embodiments, the injection section 1300may include multiple supply ports 1340 fluidly connected to separatepressurized sources of fluid additive. In such an embodiment, theannular internal peripheral reservoir manifold R′ may be divided intomultiple segregated quadrants fluidly connecting individual pressurizedsources of fluid additive to specific capillary channels 1352 allowing adistinct pattern of multiple colors and/or flavors to be imparted intothe food mass.

Referring to the figures, and in particular FIGS. 16 a, 16 b and 17 a,the exit face of the injection section 1300 is generally designed tomate and seal with the inlet face of the nozzle section 1400. An innerannular rim 1414 projecting from the inlet face of the nozzle section1400 slidably fits into a central bore formed in the outlet face of theinjection section 1300 and defined by the annular bore wall 1364, suchthat the injection section's annular outer ring seal face 1362 a seatsand seals with the nozzle section's peripheral outer seal face 1404 a,the injection section's intermediate annular seal face 1362 b seats andseals with the nozzle section's intermediate annular ring seal face 1404b, and the injection section's inner annular seal face 1362 c seats andseals with the nozzle section's inner annular ring seal face 1404 c.Thus, with the exception of the co-injection die insert 1320 and thecomplexly-shaped inlet 1410, the exit face of the injection section 1300is essentially a mirror image of the inlet face of the nozzle section1400.

While the preferred embodiment's forming and injection sections areessentially identical in form and function as the previously disclosedembodiments, the nozzle section 1400 of the preferred embodiment 1000differs in a number of aspects from the nozzle section 1400 shown inFIGS. 2 a and 2 b. Whereas the nozzle section 400 of previouslydisclosed embodiments included an inlet with a periphery matching theperiphery of the forming section's passageway, the nozzle section 1400of the preferred embodiment 1000 includes an inlet 1410 having acomplexly shaped periphery which is larger than the periphery of theextrudate passageway extending through the forming section and injectionsections. Thus, in operation, that portion of the extrudate flow intowhich a colored and/or flavored pattern has been imparted is positionedwithin the periphery of the inlet 1410.

As with the previously described embodiments, the nozzle section 1400further includes a passageway 1420 coaxially aligned with the formingsection's passageway which converges to an outlet 1430. However, whereasthe previously disclosed embodiment of the nozzle section passageway 420generally maintains its aspect ratio as its cross-sectional area isdecreased, the nozzle section 1400 of the preferred embodiment 1000shown in FIG. 14 b includes a crucial modification. As shown mostclearly in FIG. 17 a, the periphery of inlet 1410 does not have the samegeometric shape as the periphery of outlet 1430. Instead, for example,the complexly-shaped cross-sectional area that converges over its axiallength from an inlet 1410 to an outlet 1430 resembles a baseball glovein one preferred embodiment. Indeed, while the outermost portions of theperiphery of inlet 1410 generally maintain their aspect ratio to oneanother as the passageway 1420 converges to outlet 1430, those portionswhich essentially define the complex shape do not. Thus, as shown bestshown in FIGS. 14 b and 17 a, the passageway 1420 includes axiallyaligned ridgelines (e.g., 1420 a, 1420 b, 1420 c) positioned at specificperipheral points. The various peripheral points correlate to thosegeometric points that define the complex shape from a simple shape(e.g., a circle). As the passageway 1420 converges to outlet 1430, theaxially aligned ridgelines (e.g., 1420 a, 1420 b, 1420 c) graduallyproject into the bore of the nozzle passageway 1420. Thus, as theflowing extrudate passes through the nozzle section 1400, the axiallyaligned ridgelines (e.g., 1420 a, 1420 b, 1420 c) gradually disrupt theaxial flow of the extrudate at the specific peripheral points, therebyaltering the extrudate's velocity profile. By gradually disrupting theaxial flow of the extrudate in close proximity to the projectingridgelines in the converging nozzle prior to its extrusion, thedimensional quality of the resulting direct expanded food piece isgreatly improved. In addition, by carefully positioning the capillarychannels 1352 of the injection section 1300 into that portion of theflowing extrudate not affected by the axially aligned ridgelines, adistinct colored and/or flavored pattern may be imparted into theextrudable food mass during the extrusion process. Moreover, thedistinct pattern maintains its aspect ratio as it is compressed in theconverging nozzle prior to its extrusion. Thus, as shown in FIG. 18, theresulting food piece 70A not only exhibits an improved three-dimensionalquality such that each of the appendages 72 a′-72 d′ is more clearlydefined and distinguishable, but also includes a distinct colored and/orflavored pattern 76A, which resembles a baseball in one preferredembodiment, imparted in the center portion 74A of the resulting foodpiece 70A.

It will now be evident to those skilled in the art that there has beendescribed herein an improved extruder die assembly and method for usingthe same to impart a distinct colored and/or flavored pattern into anextrudable food mass while improving the quality of dimensional designaspects of the resulting extruded, complexly shaped, direct expandedfood products.

Although the invention hereof has been described by way of a preferredembodiment, it will be evident that other adaptations and modificationscan be employed without departing from the spirit and scope thereof. Theterms and expressions employed herein have been used as terms ofdescription and not of limitation; and thus, there is no intent ofexcluding equivalents, but on the contrary it is intended to cover anyand all equivalents that may be employed without departing from thespirit and scope of the invention.

1. An apparatus for improving the dimensional quality ofcomplexly-shaped, direct expanded food products having a distinctpattern imparted therein, comprising: (a) an internal peripheralreservoir manifold fluidly connected to at least one capillary channelfor supplying at least one continuous, curvilinear band of fluidadditive, said reservoir manifold formed by two interlocking sections;(b) means for supplying an extrudate flow having said distinct patternimparted into a portion of its lateral cross-section by said fluidadditive, wherein said supplying means comprises a first passageway; (c)an extrusion nozzle section having a nozzle bore formed therethrough andfluidly connected to said first passageway, said nozzle section having acomplexly-shaped inlet and said nozzle bore having a complexly-shapedcross-sectional area that converges over its axial length from saidinlet to a complexly-shaped outlet, and includes at least one axiallyaligned ridgeline that gradually projects along the entire length of thenozzle bore as said nozzle bore converges; wherein said inlet has aperiphery which circumscribes the first passageway.
 2. The apparatus ofclaim 1, wherein said axially aligned ridgeline disrupts the extrudateflow in close proximity to said ridgeline.
 3. The apparatus of claim 2,wherein said axially aligned ridgeline does not disrupt said portion ofthe extrudate flow having the distinct pattern imparted into its lateralcross-section.
 4. The apparatus of claim 3, wherein the complexly-shapedcross-sectional area resembles a baseball glove.
 5. The apparatus ofclaim 4, wherein the distinct pattern imparted resembles a baseball. 6.The apparatus of claim 5, wherein the cross-sectional area of theconverging nozzle bore is reduced by a factor less than 20:1 between theinlet and the outlet of the extrusion nozzle bore.
 7. The apparatus ofclaim 5, wherein the cross-sectional area of the converging nozzle boreis reduced by a factor greater than 4:1 between the inlet and the outletof the extrusion nozzle bore.
 8. An apparatus for improving thedimensional quality of complexly-shaped, direct expanded food productshaving a distinct pattern imparted therein, comprising an extrusionnozzle having a passageway formed therethrough and an annular internalperipheral reservoir manifold formed by two interlocking sections andfluidly connected to at least one capillary channel through which atleast one continuous, curvilinear band of fluid additive may besupplied; said passageway having a complexly-shaped cross-sectional areathat converges over its axial length from complexly-shaped inlet to anoutlet, and includes at least one axially aligned ridgeline thatgradually projects into the passageway as said passageway converges. 9.The apparatus of claim 8, wherein the complex-shaped cross-sectionresembles a baseball glove.
 10. The apparatus of claim 8, wherein thecross-sectional area of the converging passageway is reduced by a factorless than 20:1 between the inlet and the outlet of the extrusion nozzle.11. The apparatus of claim 8, wherein the cross-sectional area of theconverging passageway is reduced by a factor greater than 4:1 betweenthe inlet and the outlet of the extrusion nozzle.
 12. The apparatus ofclaim 1, wherein said continuous, curvilinear band of fluid additive issupplied through the entire exit face of said capillary channel.
 13. Theapparatus of claim 8, wherein said continuous, curvilinear band of fluidadditive is supplied through the entire exit face of said capillarychannel.
 14. The apparatus of claim 1, wherein said interlockingsections seal said reservoir manifold.